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E. W. ALEXANDER & H. GROSWITH.

CONDUCTOR COIL FOR ARMATURES AND FIELD MAGNETS AND METHOD OF MAKING SAME.

No. 529,992. Patented Nov. 27, 1894.-

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Unrrsn STATES PATENT Genres.

EMRA W. ALEXANDER AND HENRY GEOSWITH, OF PHILADELPHIA, PENN- SYLVANIA.

CONDUCTOR-COIL FOR ARMATURES AND FIELD-MAGNETS AND METHOD OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 529,992, dated November 27, 1894.

Application filed September 22,1893- Serial No. 1 (NO modem To all whom it may concern.-

Be it known that we, EMRA W. ALEXANDER and HENRY GROSWITH, of the city of Philadelphia, in the State of Pennsylvania, have invented a new and useful Improvement in Gonductor-Ooils for Armatures and Field-Magnets and other Electrical Apparatus, of which the following is a description, referring to the accompanying drawings, which form a part of this specification.

Our invention includes a method of forming or manufacturing such coils and several improvements in the coils themselves as will hereinafter more fully appear.

Briefly the improvement in the art consists in enameling a bobbin and then winding a single layer of the conducting wire with suitable space between adjacent convolutions. This spacing may be efiected by winding a separating cord parallel with and between the convolutions of the wires, which cord may be removed when a single layer or wrapping has been completed. The layer of coil is then coated with enamel in any suitable Way, entirely insulating the convolutions of the coil. After this a second layer of winding may be similarly wound and enameled, and the process carried on until the desired number of layers or length of coil has been obtained.

As a modification of the improvement in the art we Wind the conductors upon a temporary bobbin, and after the enameling has been finished we may remove the bobbin leaving the enamel coil intact.

The object of our invention is to provide a thoroughly heat-proof and water-proof insulation thus providing against burning out, short circuits and mechanical injury to the windings, and at the same time effecting a very simple, inexpensive and highlyinsulated coil. If desired the coils may be formed and enameled and then mounted upon an enamel core or spool and then the whole subjected to heat and fused into a compact integral mass. From this it will be seen that one great advantage of our construction is its rigidity combined with its high insulation. The many other advantages are apparent and readily appreciated by those skilled in the art.

Such briefly is our invention. Its details and certain of its features will be more fully understood from the accompanying drawings, wherein Figure 1, shows a single layer of winding partially wound with suitable spacing upon a spool or bobbin. Fig. 2, shows the same spool or bobbin when the second layer of winding is partially formed. Fig. 3 is a cross-section of spool and coil showing the details of the completed invention.

Throughout the figures like letters of reference indicate like parts.

In the figures the spool or bobbin is indicated by B. As already explained, this may be a temporary former or may be permanent and form an integral part of the coil. The spool may be of any suitable material, being preferably in some instances of magnetic material and in otherinstances of insulating material according to the use to which the coil is to be put. The bare conductor 0 is wound upon the spool with su'fficient insulating space between successive turns or con volutions. This spacing may be effected by winding a spacing cord S at the same time and parallel with the conductor, as clearly seen in Fig. 1. When the layer is completed the spacing cord S may be unwound leaving suitable intervals between the turns of the conductor. The enamel is then applied around and over the conductor filling in the spaces between the turns, as clearly seen in Fig. 3, and indicated by the letter E. If desired the second layer of conductor may be wound while the enamel is still somewhat soft so that the second layer may sink in between the coils of the first layer as in Fig. 3, or the enamel may be laid smoothly over the first layer and fused, or subjected to heat until thoroughly hardened. If desired also, the enamel may be depressed in grooves for the second layer and then hardened giving the corrugated surface shown at E in the lower part of Fig. 2, and also shown in Fig. 3. This grooving may be done by a large grooving strand equal in diameter to the distance between centers of adjacent conductor turns, or by a stifi molding bar, or may be accomplished by applying the enamel in a layer thin enough to follow the contour of the winding beneath. Where such grooving is employed the second layer of coil may be readily wound without special care or the use of a spacing cord, as it will lie in the grooves formed between the convolutions of the lower coil. After the second layer is wound it is coated with enamel and finished as above. When sufficient number of layers have been wound the enamel may be spread smoothly over the last layer of coil and hardened. It is apparent, and is indicated in Fig. 3, that each turn of the wire is embedded and thoroughly surrounded by the enamel. The latter, possessing a high insulating resistance, forms an almost perfect insulation, waterproof and heat-proof. Moreover, the enamel binds the whole coil together as a compact and rigid mass making the use of the coil very simple and reliable, and making it possible to have a series of interchangeable coils for electrical apparatus whereby an injured coil may be readily replaced by a new one with great sureness of fit, just as in the case of machinery formed with interchangeable parts.

To remove a coil re-fusing is not always necessary, as certain forms of coil with certain compositions of enamel may be loosened and removed by breaking or cracking the enamel. The new coil may then be put in place and cemented by fused enamel as before.

In making armatures for dynamos and motors, our improvement possesses peculiar adaptability for the armature core may be coated with enamel and the complete enamel coils placed upon it and then the whole subjected to heat, fusing the enamel and making the armature and its windings one rigid part. The advantages of this construction are too apparent to need further explanation.

In the foregoing description we have set forth one embodiment of ourinvention. We have not attempted to explain or enumerate any of the many minor variations and modifications which may be made Without departing from the principles of the invention, because so to do would obscure rather than make clear the more essential features.

Having, however, fully explained one form of our improved coil and one way in which our improvement in the art may be carried out, we claim as our own, and desire to secure by these Letters Patent, together with all modifications which may be made by mere mechanical skill, the following:

1. The herein described improvement in the art of manufacturing conductor coils, which consists of winding the conductor upon the core or spool, covering the layer of conductor so formed with enamel, depressing the enameled surface into grooves for receiving the second layer of winding, winding a second layer of conductor in such depressions or grooves, covering the second layer of conductor so formed with enamel, and thereafter, when the required number of layers have been wound, subjecting the enameled coil to heat, substantially as and for the purposes set forth.

2. The herein described improvement in the art of manufacturing conductor coils which consists in winding a conductor with a spacing cord and thereafter removing the cord and covering the winding with enamel, substantially as and for the purposes set forth.

3. As an article of manufacture a conductor coil formed of Wire embedded in enamel and fitted to the core for which it may be designed, whereby it may be applied or removed complete, and may be secured in place by fusing either directly or with additional enamel, substantially as and for the purposes set forth.

4:. The improved armature of field magnet construction, consisting of complete coils of conductor embedded in enamel, and a core or cores, the said coils being secured in place by the enamel or other fused cement, forming a rigid waterproof construction from which the coils may be removed and replaced without unwinding, substantially as and for the purposes set forth.

In testimony whereof we have hereunto set our hands, in the presence of the undersigned witnesses, this 14th day of September, 1893.

EMRA WV. ALEXANDER. HENRY GROSYVITH.

Witnesses:

WM. J. DIVINE, THOS. G. HUNTER. 

